Motor control.



J. F. TRITLE.

MOTOR CONTROL.

APPLIOATIQN FILED JULY 15, 1908.

Patented Jan. 3, 1911.

In vent or:

Witnss:

JohnF.T1-itIe, 5 7

.IXIULH.

' series with respect =..tO the other phase.

reference to the accompanying drawing,

To all whom it may concern:

usefulImprovements in Motor Control, of

to an intermediate point on the short-cir- JOHN F. TRITLE, OFSCHENECTADY, NEW

YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.,

MOTOR CONTROL.

Be it known that I, JOHN F. Tnrrnn, a citizen of the United States,residing at Schenectady, county of Schenectady, State of New York, haveInvented certain new and which the following is a specification.

My invention relates to the control of electric motors by means ofresistances. While, in its broader aspect, it is not limited to thecontrol of induction motors, it is particularly applicable to motors ofthat type hav ing resistances in circuit with the secondary, which areto he cut out step-by-step as the motor starts. It has been customaryheretofore, in the control of such motors, to employ switches forsuccessively short-circuiting portions of the resistances.

My invention consists in so arranging the short-circuiting switches thatnot only are certain portions directly short-circuited, but thatotherportions are connected in parallel with each other, before they areshort-circuited. In this manner, with a given number of resistancesections and short-circuiting switches,I am enabled to obtain a reaternumber of resistance steps than were ieretofore obtainable. Forinstance, in the case of a three-phase arrangement of resistancesconnected in Y,-after short-circuiting a portion of the resistances forone phase, I -may establish a connection from another phase cuitedportion, thereby connecting two sections of the short-circuited portionof one phase in parallel with each other and in My. invention will bestbe understood by which shows diagrammatically a motorcontrol systemarranged in accordance with my invention.

The drawing shows diagrammatically a motor-control -system.-adapted forthe control of polyphase induction motors on a car or vehicle.

.A re resents-the current-collectors-or trolleys, w ich are shown as ofthe bow-trolley t e.

represents the main switches in series with the-primary windings of-thestepdo'wn transformer .C,-to the secondaries of which Specification ofLetters Patent.

Application filed July 15, 1908.

the motor or motors D are connected.

E to E inclusive, represent resistances Patented Jan. 3,1911. Serial N0.443,612.

connected in circuit with the secondary of the motor D through collectorrings (Z and d The connection of the resistances shown 1s the threephase Y-connection, com prismg three groups of'resistances bne in eachphase; the groups having a common terminal e, .lar case shown,comprising three resistance sections.

If to F inclusive, represent electromagnetically-actuated switches forshort-circuiting the resistances step-by-step to control the motors...Certain of these switches are provided with interlocking contacts f f fand f", as shown. i

G- represents a master controller controlhug the circuit of theactuating windings of the short-circuiting switches. This controller isshown diagrammatically, with its contacts developed on a plane surface.It comprises ten stationary contact-fingers g to g", the fingers g tobeing numbered to correspond to the electromagnetically-actuatedswitches orcontactors which they co'n-' trol. The movable portion of theswltch is arranged for twelve positions indicated by the'dotted lineslto -12. i

A t starting the switch G is in the oil position, as shown, so that whenthe rimary clrcuit of the motor D is closed, the motor. starts with. allthe resistance in its secondary circuit. WVhenswitch G is moved to itsfirst operative position, contact-fingers g and g are connected to eachergizing contactor F This contactor shortcircuits the resistance 1E. Inits second position, switch G energizes contactor ,F whichshort-circuits :resistanc'e E third position, switch G energizescontactor F which short-circuits resistance E lVhen switch G is moved[to its fourthgpm sition, .contactor F is energized, short-circuiting.resistance Et, as well as resistance E and contactor F is deenergized.Up to.

this point, the arrangement of'short circuiting switches 1sthatordinarily employed.

When switch 1G is moved to its fifth posi:

tion, vhowever, a novel 'connection is estab-' lished. If contactor Fhas fallen, contactor F is energized. The actuating circuit of thiscontactor is run through interlocking contact f oncontactor 1*, aces toprevent the energization of cont-actor .F, until contactor F has'fallen.Contactor F 5 is'pro-- other, thereby en- In its 7 IE and E. Theseresistances E and E are short-circuited inseries by the contactor F butthe connection established by the contactor F throws these tworesistance sections-E and E into parallel with each other and intoseries with the phase of the motor secondary to which collector ring dis connected. In other'words, while the cir cuit from collector ring (Zto the common terminal 6 of the resistances passes through resistance Eand contacts of contactor F the circuitfrom the collector ring (Z passesthrough the contacts of contactor F and then through resistance sectionsE and E, in. parallel. Furthermore, there is another path from collectorring (Z to common re sistance terminal 6, through resistance sec- .tionsE and E and contactor F Resistance sections E and E in series are thusthrown in parallel with resistance sections E and E, in the circuit ofcollector ring (5 When switch G is moved from position 5 to position 6,contactor F is energized, shortcircuiting both resistance sections E andE and contactor F is then deenergized. Passing to position 7, contactorF is energized, short-circuit-ing resistancesE and E while contactor Fis deenergized. This-cuts re-' sistance section E out of circuit, andplaces resistance E alone in parallel with resistances E and E. Inpassing to position 8, switch G energizes contactor F which establishesa connection from collector ring al to the junction of resistances E andE. This places three resistancesin parallel between collector ring d andcommon resistance terminal 6. The path of these three resistances may betraced as follows: from collector ring (Z through resistance E andcontactor F to terminal a, and from collector ring (5 through contactorF and thence dividing, part passing through resistance E, directly toterminal a, and the other through resistance E and contactor F toterminal a. In passing from position 8 to position 9, switch G againenergizes contactor F which shortcircuits resistance E and conseqnent-lyconnects collector ring 1? directly to terminal a. This circuit may betraced from collector ring al through contactors F and F When switch Gis moved from position 9 to position 10, collector ring (1 is connected'directl to common terminal 6, since contactor F is a ain energized, sothat a circuit may be traced from collector ring (1 through contactors Fand F in series to common terminal 6. Contactors F and Fbeing no longerrequired, are now deenergized. In moving from position 10 to position11, contactor F is energized, provided contactor F has fallen, thesetwocontactors being rovided with interlocking contacts, like t ose forcontactors F and F. The closing of contactor F connects collector ring dto the junction off-resistances E and E, and thereby establishesparallel circuits from collector ring (i to common terminal 6. One ofthese circuits passes from collector rin (i through resistance E andcontactor Another circuit passes from collector ring d through contactorF to the junction of resistances E and E Here the circuit divides, one

tactors F and F in series, while the other passes through resistances Eand E in series. In passing from position 11 to position 12 of switch G,contactor F 'is again energized, thereby establishing a directconnection from collector ring (1 through contactors F and F in series,to terminal 0. Gontactor F being no longer required is deenergized.

With the arrangement of switches above described, twelve diiferentresistance conditions are obtained, in addition to the startingcondition with all resistances in series, and these twelve steps areobtained with nine resistance sections and nine contnctois, which, inthe ordinary arrangement, would give only nine resistance steps. Itwill, of course, be understood that the principle of control, abovedescribed, may be further extended. In order to get the propergradations of resistance, the several resistance sections should beproperly proportioned. The diagram roughly indicates suitable portionsof the resistances for the particular control shown.

I do not desire to nnut myselI to the particular construction andarrangement of parts here shown, but aim in the appended claims to coverall modifications WhlCll are within the scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is,-

1. In combination'with an induction motor, a three-phase arrangement ofresistances connected in Y in series with the secondary of said motor,-and switches arranged to short-circuit portions of the resistance foreach phase and to establish a connection from one phase to anintermediate point of the resistance for a different phase, wherebycertain ortions of said resistances are connected 1n parallel beforethey are shortcircuited.

2. In combination with an induction motor, a three-phase arrangement ofresistances connected in Y in series with the secondary of said motor,and switches arranged to short-circuit portions of the resistance foreach phase and to establish a connection from one phase to anintermediate point on a short-circuited portion of the resistance foranother phase whereby two sections of side passing throu h resistance Eand consaid short-oircuited portion are connected in parallel with eachother in series with the first phase.

3. In combination with an electric motor, a plurality of resistances incircuit therewith having a connnon tern'iinal, and switches ar ranged toshort-circuit portions of said resistances and to establish a connectionfrom one resistance. to an intermediate point on another resistancewhereby certain portions of said resistances are connected in parallelbefore they are short-circuitcd.

l. in combination with an electric motor, a plurality of resistances incircuit therewith having a common terminal, and switches aranged toshort-circuit portions of said resistances and to establish a connectionfrom one resistance to an intermediate point on a short-circuitedportion of another resistance whereby two sections of saidshort-circuited portion are connected in parallel with each other and inseries with respect to said connection.

5. In combination with an electric motor, resistances in. circuit withsaid motor, electromagneticaIly actuated switches arranged tosl'iort-circuit portions of said resistances and to connect certainportions in parallel with other portions before short-circuiting them,and a control system controlling the circuits of the actuating windingsof said switches. v

G. In combination with an electric motor, resistances in circuit withsaid motor, electromagnetically-actuated switches arranged toshort-circnit portions of said resistances and to establish a pluralityof parallel con nections between certain portions of said resistancesbefore short-circniting them, and a control system controlling thecircuits of the actuating windings of said switches.

7. In combination with an electric motor, a plurality of resistances incircuit therewith having a common terminal,electromagnctically-act'uated switches arranged to shortvcircnitportions of said resistances and to establish a connection from oneresistance to an intermediate point on another resistancewhereby certainportions of said resistances are connected in parallel before they areshort-circuited, and a control system controlling the circuits of theactuating windings of said switches.

8. In combination with an induction m0- tor, a three-phase arrangementof resistances connected in Y in series with the secondary of saidmotor, electromagnetically-actuated switches arranged to short-circuitportions of the resistance for each phase and to establish a connectionfrom one phase to an intermediate point on a short-circuited portion ofthe resistance for another phase whereby two sections of saidshort-circuited portion are connected in parallel with each other inseries with the first phase, and a control system controlling thecircuits of the actuating windings of said switches.

In witness whereof, I have hereunto setmy hand this 8th day of July,1908.

' JOHN F. TRITLE.

\Vitnesses HELEN Onronn, FRANK J. Donn.

